Catheter assembly for delivering a radiation source into a body cavity

ABSTRACT

A catheter assembly for delivering a radiation source into a body cavity includes a catheter shaft having a distal end and a proximal end. An inflatable balloon is coupled to the catheter shaft between the distal end and the proximal end. A dose delivery lumen extends along the catheter shaft between the proximal end and the distal end. The dose delivery lumen is configured to receive the radiation source. A radioabsorptive portion is surrounded by the inflatable balloon.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. patent application Ser. No.11/155,789, entitled “VACUUM DEVICE AND METHOD FOR TREATING TISSUEADJACENT A BODY CAVITY”, filed Jun. 17, 2005, now U.S. Pat. No.7,935,044 which is a continuation of U.S. patent application Ser. No.10/290,002 filed Nov. 6, 2002, now U.S. Pat. No. 6,923,754, each ofwhich is incorporated herein in its entirety by reference and from whichpriority is claimed.

FIELD OF THE INVENTION

This invention relates generally to the fields of medical treatmentdevices and methods. In particular, the invention relates to devices andmethods for treating tissue surrounding a body cavity, such as a sitefrom which cancerous, pre-cancerous, or other tissue has been removed.

BACKGROUND OF THE INVENTION

In diagnosing and treating certain medical conditions, it is oftendesirable to perform a biopsy, in which a specimen or sample of tissueis removed for pathological examination, tests and analysis. A biopsytypically results in a biopsy cavity occupying the space formerlyoccupied by the tissue that was removed. As is known, obtaining a tissuesample by biopsy and the subsequent examination are typically employedin the diagnosis of cancers and other malignant tumors, or to confirmthat a suspected lesion or tumor is not malignant. Treatment of cancersidentified by biopsy may include subsequent removal of tissuesurrounding the biopsy site, leaving an enlarged cavity in the patient'sbody. Cancerous tissue is often treated by application of radiation, bychemotherapy, or by thermal treatment (e.g., local heating, cryogenictherapy, and other treatments to heat, cool, or freeze tissue).

Cancer treatment may be directed to a natural cavity, or to a cavity ina patient's body from which tissue has been removed, typically followingremoval of cancerous tissue during a biopsy or surgical procedure. Forexample, U.S. Pat. No. 5,429,582 to Williams, U.S. Pat. No. 5,913,813 toWilliams et al., U.S. Pat. No. 5,931,774 to Williams et al., U.S. Pat.No. 6,022,308 to Williams, U.S. Pat. No. 6,083,148 to Williams, and U.S.Pat. No. 6,413,204 to Winkler et al., the disclosures of which are allhereby incorporated by reference in their entireties, describe devicesfor implantation into a cavity resulting from the removal of canceroustissue which can be used to deliver cancer treatments to surroundingtissue. One form of radiation treatment used to treat cancer near a bodycavity remaining following removal of tissue is “brachytherapy” in whicha source of radiation is placed near to the site to be treated.

Williams and coworkers describe implantable devices for treating tissuesurrounding a cavity left by surgical removal of cancerous or othertissue that includes an inflatable balloon constructed for placement inthe cavity. Such devices may be used to apply one or more of radiationtherapy, chemotherapy, and thermal therapy to the tissue surrounding thecavity from which the tissue was removed. The balloon may be filled witha treatment fluid delivered via a conduit from a receptacle, syringe, orother means, or may receive a solid radiation source placed within theballoon. Thus, radiation treatment may be applied to tissue adjacent theballoon by placing radioactive material such as radioactive “seeds”within the balloon, or by filling the balloon with a liquid or slurrycontaining radioactive material. Multiple treatments may be appliedsimultaneously. For example, radioactive seeds may be placed within theballoon effective to irradiate tissue surrounding the balloon, and theballoon filled with a hot fluid at the same time to provide thermaltreatment. After a suitable time, the hot fluid and/or the radioactiveseeds may be removed. Such treatments, combined or otherwise, may berepeated if desired.

For example, a “MammoSite® Radiation Therapy System” (MammoSite® RTS,Proxima Therapeutics, Inc., Alpharetta, Ga. 30005 USA) includes aballoon catheter with a radiation source that can be placed within atumor resection cavity in a breast after a lumpectomy. It can deliver aprescribed dose of radiation from inside the tumor resection cavity tothe tissue surrounding the original tumor. The radiation source istypically a solid radiation source; however, a liquid radiation sourcemay also be used with a balloon catheter placed within a body cavity(e.g., Iotrex®, Proxima Therapeutics, Inc.). The radiation source may beremoved following each treatment session, or may remain in place as longas the balloon remains within the body cavity. Inflatable treatmentdelivery devices and systems, such as the MammoSite® RTS and similardevices and systems (e.g., GliaSite® RTS (Proxima Therapeutics, Inc.)),are useful to treat cancer in tissue adjacent a body cavity.

However, radiation, chemotherapy, thermal treatment, and other cancertreatments often have deleterious effects on healthy tissue in additionto the desired effects on cancerous tissue. In such treatments, caremust be taken to direct the maximum treatment effects to diseased tissuewhile minimizing its delivery or effects on healthy tissue. For example,radiation treatment may be most effective when all surrounding tissueregions receive the same dose of radiation, and where the radiationdosage received by more distant tissue is as small and as uniform aspossible. However, tissue cavities typically are not uniform or regularin their sizes and shapes, so that differences in dosages applied todifferent regions of surrounding tissue, including “hot spots” andregions of relatively low dosage, often result from radiation treatment.

Thus, there is need in the art for improved devices and methods fordelivering cancer treatment to a cavity site within a patient's body.

SUMMARY OF THE INVENTION

The invention provides assemblies, devices, systems, and methods fortreating tissue adjacent a body cavity, such as a cavity formed by theremoval of tissue from a patient. In methods and devices having featuresof the invention, vacuum is applied effective to draw tissue towards atreatment assembly placed within the body cavity. Assemblies and devicesembodying features of the invention include a vacuum delivery elementconfigured to apply a vacuum. A vacuum delivery element may include avacuum conduit, and may further include a vacuum port. A vacuum deliveryelement may be configured to at least partially surround or enclose atreatment assembly. A treatment assembly may be configured to deliver atreatment, such as radiation therapy, chemotherapy, thermal therapy, orother treatment, to tissue adjacent a body cavity. A treatment assemblymay include a treatment delivery element configured to contain atreatment material, such as a radioactive source. A treatment assemblymay include an inflatable balloon, which may be disposed at least inpart around a treatment delivery element.

Assemblies and devices embodying features of the invention may include avacuum delivery element such as a sheath or a balloon configured toprovide vacuum effective to apply suction to tissue adjacent theassemblies and devices. Vacuum delivery elements are preferablyconfigured to apply suction to tissue adjacent a treatment deliveryassemblies, such as an inflatable treatment delivery device. Suction iseffective to draw surrounding tissue close to the surface of a treatmentassembly, or to a vacuum delivery element (such as a sheath or balloon)at least partially surrounding or enclosing a treatment assembly, so asto shape the tissue lining the body cavity for optimal treatment.Treatment may be by, e.g., radiation therapy, chemotherapy, thermaltherapy, or other treatment modality supplied by the device. A treatmentassembly may include an inflatable treatment assembly such as an innerballoon assembly configured to be at least partly enclosed by a vacuumdelivery element such as a sheath or balloon. A sheath may be configuredto at least partly enclose a balloon temporarily, following placementover or around an inner balloon. A balloon may be configured to at leastpartly enclose a balloon permanently following placement over or aroundan inner balloon.

Devices may further include an enclosure assembly (which may comprise asheath assembly or a balloon assembly) comprising a vacuum conduit and afluid-permeable enclosure wall (e.g., a sheath wall or a balloon wall)configured to partly or completely enclose an inner balloon assembly.Such an enclosure assembly may be effective to provide vacuum and avacuum path to an intermediate space outside the inner balloon assembly.An intermediate space may include a space disposed between the innerballoon assembly and a sheath assembly or an outer balloon assembly. Theenclosure assembly is preferably operatively connected to a vacuumconduit effective to provide vacuum to the intermediate space. Systemshaving features of the invention include such devices and furtherinclude a vacuum source configured to operatively connect with thevacuum conduit. In embodiments of devices having features of theinvention, a fluid-permeable enclosure wall may have a hole or multipleholes configured to allow passage of fluid, may be made with afluid-permeable material, such as a fluid-permeable woven material, ormay be otherwise fluid-permeable. The space between the inner balloonand the enclosure may be prevented from collapse, even in the presenceof suction from a vacuum delivered via the vacuum conduit, by separationelements disposed on the inner balloon wall, or on the enclosure wall,or both. In alternative embodiments, separation elements disposed withinan intermediate space may be independent of both the inner balloon walland the enclosure wall.

An embodiment of a device for treating tissue adjacent a body cavityhaving features of the invention further comprises an inner balloonassembly, which may include or be operatively connected with aninflation conduit configured to allow passage of a fluid. Devices mayalso have an inner balloon comprising a distensible inner balloon walldefining an internal lumen. Such an inner balloon may be operativelyconnected to an inflation conduit so as to allow for passage of fluidthrough an inflation conduit and into the internal lumen so as toinflate the inner balloon with the fluid.

An enclosure wall preferably comprises a flexible material, morepreferably an elastic flexible material, although in embodiments of theinvention, an enclosure wall may comprise an inelastic flexiblematerial. In embodiments of devices and systems having features of theinvention, an enclosure wall comprises a polymer, such as biocompatiblepolymer, preferably a radiation-resistant polymer. Suitable polymersinclude polyolefins such as polyethylene and polypropylene,polyurethanes, polyester, polyvinylchloride, polystyrene, thermoplasticpolymers such as C-Flex® (Consolidated Polymer Technologies, Inc.,Clearwater Fla. 33762), block polymers such as Kraton™ (Kraton Polymers,Houston Tex. 77208), an ionomer such as Surlyn® (Dupont, Wilmington Del.19880), nylon, latex rubber, and silicon rubber (e.g., SILASTIC™, DowCorning, Midland, Mich.).

Devices and systems having features of the invention include innerballoon assemblies configured to enclose a treatment material, such asradioactive material, chemotherapeutic agents, and thermal treatmentmaterials (e.g., materials having a temperature greater than about 37°C.).

The invention further provides methods for treating tissue adjacent abody cavity, comprising contacting tissue adjacent a body cavity with asheath or an outer balloon having a fluid-permeable wall of a devicehaving features of the invention; and applying a vacuum effective toenhance the contact between the fluid-permeable wall and the tissue.Further methods may include delivering inflation fluid to an innerballoon lumen via an inflation conduit to inflate a distensible balloon.In embodiments of the methods of the invention, the inner balloonassembly comprises a treatment assembly such as a Mammosite RTS orsimilar inflatable treatment delivery device. Methods may includeplacing a treatment material within the device, and may further includereplacing the treatment material.

Body cavities are typically not uniform in size or regular in shape.Devices, systems and methods having features of the invention utilizesuction to draw tissue against the device surface within a body cavity,insuring good contact between the device and body tissue and providingcontrol over the spacing between tissue and the device, includingcontrol over the distance from the treatment material contained withinthe devices. Tissue lining a body cavity that is held close to, or incontact with, devices having features of the invention forms a uniformand controlled surface, unlike tissue lining a body cavity in which aprior art treatment device has been merely inserted, but which does noturge tissue into a desired orientation and position. The control overthe distance, spacing, and amount of tissue contact provided by devices,systems and methods of the present invention offer the advantages ofimproved treatment tissue adjacent a body cavity. Such improvements mayinclude more uniform dosing, reduction of “hot spots,” shortertreatments due greater correlation between desired and actual dosages,and reduction in the number of locations receiving inadequate dosages.

The invention, in one form thereof, is directed to a catheter assemblyfor delivering a radiation source into a body cavity. The catheterassembly includes a catheter shaft having a distal end and a proximalend. An inflatable balloon is coupled to the catheter shaft between thedistal end and the proximal end. A dose delivery lumen extends along thecatheter shaft between the proximal end and the distal end. The dosedelivery lumen is configured to receive the radiation source. Aradioabsorptive portion is surrounded by the inflatable balloon.

The invention, in another form thereof, is directed to catheter assemblyfor delivering a radiation source into a body cavity. The catheterassembly includes a catheter shaft having a distal end and a proximalend. An inflatable balloon is coupled to the catheter shaft between thedistal end and the proximal end. A dose delivery lumen extends betweenthe inflatable balloon and the proximal end of the catheter shaft. Avent system includes one or more vents positioned along an outer surfaceof the inflatable balloon, and one or more vent lumens extending betweenthe proximal end of the catheter shaft and the one or more vents.

The invention, in another form thereof, is directed to catheter assemblyfor delivering a radiation source into a body cavity. The catheterassembly includes an elongate shaft which has a proximal shaft portion,a distal shaft portion and a treatment location in the distal portion. Acavity filling member is located on a distal shaft portion surroundingthe treatment location. The cavity filling member has an exteriorsurface. The cavity filling member is configured to at least partiallyfill the body cavity. At least one spacing member extends from theexterior surface of the cavity filling member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is partially cut-away perspective view of a system embodyingfeatures of the invention shown configured to deliver a treatment withina cavity in a patient's body tissue while providing vacuum effective tourge tissue into contact with an outer balloon surface.

FIG. 2 is a longitudinal cross-sectional view of the system of FIG. 1taken along line 2-2.

FIG. 3 is a transverse cross-sectional-view of the system of FIG. 1taken along line 3-3.

FIG. 4A is a cross-sectional view of a system of FIG. 1 showing apie-shaped section of balloon walls between lines 4-4 for an embodimentin which an outer wall has stand-offs.

FIG. 4B is a cross-sectional view of the system of FIG. 1 showing apie-shaped section of balloon walls between lines 4-4 for an embodimentin which an inner wall has stand-offs.

FIG. 5A shows a perspective view of a system embodying features of theinvention in which an outer balloon assembly, in the form of a sheath,is being fitted over an inner balloon assembly.

FIG. 5B shows a cross-sectional view of the assembled outer and innerballoon assemblies of FIG. 5A following placement into a cavity within abreast of a patient and before inflation of the inner balloon assembly.

FIG. 5C shows a cross-sectional view of the assembled outer and innerballoon assemblies of FIG. 5A following inflation of the inner balloonassembly.

FIG. 5D shows a cross-sectional view of the assembled outer and innerballoon assemblies of FIG. 5A following application of vacuum to thelumen separating the inner balloon assembly and the outer balloonassembly, and after placement of a radioactive assembly within the innerballoon assembly.

FIG. 6A is perspective view of a system embodying features of theinvention including a vacuum delivery element configured to partlyenclose an inner balloon assembly.

FIG. 6B is a cross-sectional view of the system of FIG. 6A taken alongline 6B-6B.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides devices and methods for delivering atreatment, such as a cancer treatment, into a cavity within the body ofan animal. For example, devices and methods having features of theinvention may be used to deliver treatments into a biopsy site or into acavity left after removal of cancerous tissue from within the body of ahuman patient. Vacuum is applied to tissue to enhance contact between atreatment delivery assembly within a body cavity and tissue surroundingthe body cavity. A vacuum path around the treatment assembly is providedby devices, systems and methods embodying features of the invention.Vacuum may be applied to tissue via one, two, or multiple vacuum ports.A vacuum port may be a port in a vacuum delivery conduit, a hole in asheath or balloon connected to a vacuum delivery conduit. A fluidpermeable wall or portion of a fluid permeable wall may be effective toserve as a vacuum port.

FIG. 1 is a perspective view of a system 10 embodying features of theinvention illustrating a device 12 having an outer balloon 14 enclosingan inner balloon 16 (shown in the cut-away portion of the illustration),a shaft 18 and connector 20. Outer balloon 14 comprises a sheathassembly around inner balloon 16. Outer balloon 14 is thus an example ofan enclosure assembly, and forms an enclosure wall around inner balloon16. Outer balloon 14 comprises at least in part a fluid permeable wall;as illustrated in FIG. 1, outer balloon 14 has holes 22 allowing fluidpermeation into and out of balloon 14. In alternative embodiments, anouter balloon 14 may be made of woven or otherwise substantiallycontinuous materials that are fluid permeable. In further embodiments,an enclosure wall or assembly such as an outer balloon may comprise anet, mesh, framework, or other discontinuous structure. Holes 22 (orfluid permeable material) allow fluids to pass through outer balloon 14into intermediate space 24 disposed outside inner balloon 16.Intermediate space 24 provides a vacuum path adjacent inner balloon 16.Where at least a portion of outer balloon 14 is disposed adjacent innerballoon 16, intermediate space 24 is disposed between outer balloon 14and inner balloon 16.

Inner balloon 16 defines an inner lumen 26, within which a deliveryshaft 28 may be at least partially contained. As shown in FIG. 2, atreatment material 30 may be permanently or transiently disposed withindelivery shaft 28. A probe 32 configured to move within delivery shaft28 may be used to position treatment material 30, including to placetreatment material 30 into and to retrieve placement material 30 from,within delivery shaft 28. A vacuum conduit 34 may be part of, or may becontained within, a shaft 18 and operatively connected to intermediatespace 24. Shaft 18 may also include or contain an inflation conduit 36configured to allow passage of inflation fluid into inner lumen 26.Passage of inflation fluid into inner lumen 26 is effective to inflateinner balloon 16. Inflation fluid may be any suitable fluid, either agas or a liquid, and is typically inert. Inflation fluid, where a gas,may be, e.g., air, nitrogen, carbon dioxide or other gas. Inflationfluid, where a liquid, may be water, saline, mineral oil, or otherliquid. In some embodiments, an inflation fluid may be effective toabsorb radiation to, for example, moderate or adjust a dosage ofradiation delivered to a patient's tissue from radioactive treatmentmaterial 30 contained within a delivery shaft 28.

Vacuum applied to intermediate space 24 is effective to deliver atreatment within a body cavity 38 within a patient's body effective tourge surrounding tissue into contact with at least a portion of thesurface of the outer balloon 14.

The outer balloon 14 shown in FIGS. 1-5 is illustrated as a balloon thatis configured to permanently or semi-permanently enclose inner balloon16 or inner balloon assembly. Such an enclosure may be partial orcomplete. It will be understood that the outer surface of a device andof a system embodying features of the invention may also be a sheath 50configured for deployment over and around an inner balloon assembly 14.In further embodiments, an enclosure may be, e.g. a net, mesh,framework, or other discontinuous structure.

FIG. 2 is a longitudinal cross-sectional view of the system of FIG. 1taken along line 2-2 showing in cross section, for example, the relativepositions of treatment material 30, an inner balloon 16, and an outerballoon 14 or sheath 50. FIG. 2 includes cross-sectional views of shaft18 including views of delivery shaft 28, vacuum conduit 34 and inflationconduit 36. FIG. 3 is a transverse cross-sectional view of the system ofFIG. 1 taken along line 3-3 showing outer balloon 14 and holes 22therethrough, inner balloon 16 disposed within outer balloon 14,delivery shaft 28 and probe 32.

FIGS. 4A and 4B show portions of outer balloon 14 and inner balloon 16as indicated in FIG. 1, including intermediate space 24 and spacers 40which serve as separation elements effective to maintain patency ofintermediate space 24 even under the influence of vacuum supplied viavacuum conduit 34. Spacers 40 may be part of outer balloon 14, or ofinner balloon 16, or both. A spacer 40 may be a bump, knob, ridge, orother feature extending inwardly from an inner surface 42 of outerballoon 14, or extending outwardly from an outer surface 44 of outerballoon 14. In addition, or alternatively, a spacer 40 may be an objectthat is placed within intermediate space 24 and is separate from outerballoon 14 and inner balloon 16. For example, as shown in FIGS. 4A and4B, spacers 40 may be stand-offs extending from an inner surface 42 ofouter balloon 14 and from an outer surface 44 of outer balloon 14.

FIGS. 5A-5D illustrate the fitting of an outer balloon assembly 46(including an outer balloon in the form of a sheath 50), over an innerballoon assembly 48 including an inner balloon 16. FIG. 5B shows theassembled outer 46 and inner 48 balloon assemblies of FIG. 6A followingplacement into a cavity 38 within a breast 52 of a patient and beforeinflation of the inner balloon assembly 48. In FIG. 5C, the innerballoon assembly 48 has been inflated by passage of inflation fluidthrough inflation conduit 36, pressing some parts of the outer surface54 outer balloon assembly 46 into contact with portions of the innersurface 56 of body cavity 38. Note, however, that since most cavities 38have irregular inner surfaces 56, there will typically be poor andintermittent contact between outer surface 54 of sheath 50 (or outerballoon 14 in alternative embodiments) and inner surface 56 of cavity38, as shown in FIG. 5C.

FIG. 5D shows the assembled outer 46 and inner 48 balloon assemblies ofFIG. 5A following application of vacuum via vacuum conduit 34 to theintermediate space 24 separating the inner balloon 16 and the sheath 50(outer balloon 14). Treatment material 30 is in place within deliveryshaft 28. Note that inner surface 56 of cavity 38 has been pulled intointimate contact with outer surface 54 of sheath 50. Such intimatecontact configures inner surface 56 into an optimal configuration forthe application of treatment by a treatment material 30. For example,radiation treatment by a radiation treatment material 30 is enhanced byproper positioning of adjacent tissue to provide proper irradiation.Irradiation levels may vary widely where the adjacent tissue of tissuecavity 38 is at different, irregular, or improper distances from aradiation source. Application of vacuum effective to draw tissue intobetter contact with device 12, e.g., into better contact with outersurface 54 of sheath 50, is effective to improve the delivery ofradiation treatment from a radioactive treatment material 30.

FIG. 6A illustrates a system embodying features of the inventionincluding a vacuum delivery element comprising an enclosure 60 havingribs 62 configured to partly enclose an inner balloon assembly 48.Vacuum is delivered to intermediate space 24 via vacuum ports 64operatively connected to vacuum conduit 34. As shown in cross-section inFIG. 6B, ribs 62 serve as separation elements effective to providevacuum paths in the intermediate space 24 between tissue surface 56 andouter surface 44 of inner balloon assembly 48.

Methods for treating tissue adjacent a body cavity 38 include methodsfor delivering a treatment to tissue adjacent a device 12 embodyingfeatures of the invention. For example, a method of treating tissueadjacent a body cavity 38 includes contacting tissue adjacent the bodycavity 38 with a sheath 50 or an outer balloon 14, and applying a vacuumvia vacuum conduit 34. The vacuum may be effective to draw adjacenttissue towards and into contact with a sheath 50 or an outer balloon 14,and so enhance the contact between the outer wall 54 and the tissue.Delivery of inflation fluid to an inner balloon 16 via an inflationconduit 36 to inflate inner balloon 16 is effective to enhance contactwith adjacent tissue as well, serving to bring outer balloon 14 orsheath 50 closer to tissue than it would be in the absence of inflationof inner balloon 16. In preferred embodiments, the inner balloonassembly 48 comprises an inflatable treatment delivery device such as aMammosite RTS (Proxima Therapeutics, Inc., Alpharetta, Ga. 30005) orsimilar device.

Methods further include placing a treatment material 30, such as aradiation source, within the device (e.g., by placement within adelivery shaft 28). A radiation source, such as a solid radiation source(e.g., a brachytherapy seeds) may be advanced into a delivery shaft 28with a probe 32 or by other means. Other solid treatment materials 30may similarly be advanced into a delivery shaft 28 with a probe 32 or byother means. A liquid radiation source (e.g., Iotrex®, ProximaTherapeutics, Inc., Alpharetta, Ga.) may be advanced into a deliveryshaft 28 by fluid flow, under the influence of gravity, pressure appliedby a syringe or other pressure source, or other means for deliveringfluid into a space. Similarly, hot liquids and other liquid treatmentmaterials 30 may be introduced into a delivery shaft 28 or an innerballoon 16 (via inflation conduit 36) under the influence of gravity,pressure applied by a syringe or other pressure source, or other meansfor delivering fluid into a space.

Some treatment regimens may include periodic or episodic treatment, inwhich radiation or other treatment is applied for a treatment period,and then the treatment is stopped for a recovery period. Such periodicor episodic treatments may be repeated, so that treatment is appliedduring a first treatment period, stopped during a first recovery period,and then treatment is re-applied for a second treatment period. Furthertreatment periods and recovery periods may also be used as necessary.Thus, methods may further include removal of a radiation source or othertreatment material 30 from within a delivery shaft 28, and may furtherinclude replacing the treatment material 30.

Although a cavity 38 is typically an artificial cavity remaining afterremoval of tissue at biopsy, surgery, or other medical procedure, a bodycavity may be a natural body cavity. For example, devices 12 may beinserted into a bladder for the treatment of bladder cancer. Applicationof suction is effective to enhance contact with a device 12 in such anexample as well. Such enhanced contact may be effective to improve thedelivery of radiation or other treatment, and may be effective to avoid“hot spots” (tissue regions receiving more radiation than is received byneighboring tissue regions) and is one of the important advantagesprovided by the present invention.

Treatment material 30 may include a chemotherapy agent effective totreat cancer or other disease condition of tissue surrounding a bodycavity 38. In preferred embodiments, treatment material 30 includes aradiation source configured to delivery radiation to tissue adjacent adevice 12.

Thus, treatment material 30 may include a radiation source which may besolid or liquid. A liquid radiation source may include, for example, aliquid containing a radioactive iodine isotope (e.g., ¹²⁵I or ¹³¹I), aslurry of a solid isotope, e.g. ¹⁹⁸AU, ⁹⁰Y, ¹⁶⁹Yb, or a gel containing aradioactive isotope. Liquid radiation sources are commercially available(e.g., from Iotrex®, Proxima Therapeutics, Inc., Alpharetta, Ga.).

A solid radiation source may include brachytherapy seeds or other solidradiation source used in radiation therapy, such as, for example aradioactive microsphere available from the 3M Company of St. Paul, Minn.A solid radioactive source can either be preloaded into a device 12 atthe time of manufacture or may be loaded into the device 12 afterplacement into body cavity 38 of a distal portion of the device 12. Suchdistal portion preferably includes the outer balloon 14, inner balloon16, and at least a portion of delivery shaft 28. Such a solidradioactive core configuration offers the advantage in that it allows awider range of radionuclides than if one is limited to liquids. Solidradionuclides suitable for use with a delivery device embodying featuresof the present invention are currently generally available asbrachytherapy radiation sources (e.g., I-Plant™, Med-Tec, Orange CityIowa).

In general, the amount of radiation desired by the physician is acertain minimum amount that is delivered to a site about 0-3 cm awayfrom the wall of the body cavity 38 (e.g., from where a tumor has beenexcised). Vacuum applied to intermediate space 24 effects good contactbetween tissue surrounding body cavity 38 and the wall of the outerballoon 14 or sheath 50, promoting effective treatment delivery, such asdelivery of radiation to surrounding tissue. It is desirable to keep theradiation in the region near the wall of the outer balloon 14 or sheath50 as uniform as possible to prevent over-exposure to tissue at or nearthe reservoir wall. It is well known that the absorbed dose rate at apoint exterior to a radioactive source is inversely proportional to thesquare of the distance between the radiation source and the targetpoint. Thus, it is possible that the radiation dosage delivered toadjacent tissue may differ from that delivered to tissue disposed atmore distal locations. In some instances, penetration of radiation tolocations far from a device 12 is not desired. For example, in treatingcancers such as bladder cancer, where the neoplastic tissue is generallylocated on the bladder surface, deep penetration is unnecessary and tobe avoided.

An inflation fluid may also be a radiation absorbing fluid. For example,an inflation fluid may be an X-ray contrast agent as used inangiography, such as a Barium salt (e.g., barium sulfate), water, salineor other such fluid. A radiation-absorbing inflation fluid, which willsurround a radiation source placed within delivery shaft 28, serves tomoderate and control the delivery of radiation from the radiation sourceto surrounding tissue. Such moderation and control that is obtained witha radiation-absorbing inflation fluid may aid in avoiding the deliveryof an excessive amount of radiation to some portions of the surroundingtissue.

Thus, in the absence of such a radiation-absorbing inflation fluid, itis possible in some instances that a radiation source sufficient toprovide an effective dose at distances removed from a device 12, wouldexpose tissue that is directly adjacent the wall of the outer balloon 14or sheath 50 to an excessive radiation dose. Such excessive exposure tosuch tissue near to the device 12 may result in necrosis of healthytissue necrosis.

Alternatively, an inflation fluid may contain radioactive elements,either as a liquid or slurry, so that the inner balloon 16 is filledwith a source of radiation, providing a fairly uniform source ofradiation that is distributed over the volume of the inner balloon 16.In such embodiments, an inflation fluid thus itself serves as aradiation source, thereby providing well-controlled amounts of radiationto surrounding tissue while minimizing irregularities in the dosagesdelivered to particular locations.

In embodiments of the invention in which an inflation fluid includes aradiation source, a delivery shaft 28 may contain a radiation absorptivematerial, so that, for example, less volume of radioactive material isrequired than if the entire volume of a device 12 were filled withradioactive material. Such a configuration may be advantageous where aprofile exhibiting higher intensity at a tissue surface with lesserpenetration is desired. Moreover, the outer balloon 14 need not bespherical, yet a uniform profile of radiation delivery is obtainable.Experiments reported in Williams U.S. Pat. No. 5,918,813 are describedas showing that a steeper radial absorbed source gradient can beobtained using a radiation attenuation fluid in an inner chamber of asimilar radiation deliver device than otherwise obtains with a devicehaving only a single distensible chamber (as described in Williams U.S.Pat. No. 5,429,582).

1. A catheter assembly for delivering a radiation source into a bodycavity, the catheter assembly comprising: a catheter shaft having adistal end and a proximal end, and an inflation conduit; an inflatableballoon coupled to the catheter shaft between the distal end and theproximal end, wherein the inflatable balloon defines an inner lumen thatextends between the catheter shaft and the inflatable balloon, the innerlumen being in fluid communication with the inflation conduit; a dosedelivery lumen extending along the catheter shaft between the proximalend and the distal end, the dose delivery lumen being configured toreceive the radiation source and deliver the radiation source to alocation within the catheter shaft that is surrounded by the inflatableballoon; and a radioabsorptive portion positioned in the inner lumenbetween the catheter shaft and the inflatable balloon, and surrounded bythe inflatable balloon.
 2. The catheter assembly of claim 1, comprising:an outer balloon positioned to surround the inflatable balloon; and avent system, the vent system including: one or more vents positionedalong an outer surface of the outer balloon; and one or more vent lumensassociated with the catheter shaft, wherein the one or more vents are influid communication with the one or more vent lumens.
 3. The catheterassembly of claim 1, wherein the catheter shaft has a vacuum lumen andat least one port in the catheter shaft proximal or distal to theinflatable balloon which is in fluid communication with the vacuum lumento facilitate application of a vacuum within the body cavity.
 4. Acatheter assembly for delivering a radiation source into a body cavity,the catheter assembly comprising: a catheter shaft including a distalend and a proximal end; an inflatable balloon coupled to the cathetershaft between the distal end and the proximal end; a dose delivery lumenextending between the inflatable balloon and the proximal end of thecatheter shaft; and a vent system including: one or more ventspositioned along an outer surface of the inflatable balloon; and one ormore vent lumens extending between the proximal end of the cathetershaft and the one or more vents.
 5. The catheter assembly of claim 4,comprising an inflation lumen extending along the catheter shaft betweenthe inflatable balloon and the proximal end.
 6. The catheter assembly ofclaim 5, comprising a radioabsorptive portion surrounded by theinflatable balloon.
 7. A catheter assembly for delivering a radiationsource into a body cavity, the catheter assembly comprising: an elongateshaft having a proximal shaft portion, a distal shaft portion and atreatment location in the distal shaft portion; a cavity filling memberlocated on the distal shaft portion surrounding the treatment location,the cavity filling member having an exterior surface, and the cavityfilling member being configured to at least partially fill the bodycavity; and at least one spacing member extending from the exteriorsurface of the cavity filling member.
 8. The catheter assembly of claim7, wherein the radiation source is provided in the treatment location inthe distal shaft portion.
 9. The catheter assembly of claim 7, whereinthe elongate shaft has an inner lumen extending to the treatmentlocation to facilitate delivery of the radiation source to the treatmentlocation.
 10. The catheter assembly of claim 7, wherein each of the atleast one spacing member is a rib oriented longitudinally on theexterior surface of the cavity filling member.
 11. The catheter assemblyof claim 7, wherein the at least one spacing member is formed integrallywith the cavity filling member.
 12. The catheter assembly of claim 7,wherein the at least one spacing member is configured to provide spacebetween the exterior surface of the cavity filling member and tissuelining the body cavity.
 13. The catheter assembly of claim 7, whereinthe cavity filling member is inflatable.
 14. The catheter assembly ofclaim 13, wherein an inflation lumen extends through the elongate shaftto an interior portion of the inflatable cavity filling member todeliver inflation fluid to an interior portion of the cavity fillingmember to inflate the cavity filling member.
 15. The catheter assemblyof claim 14, wherein the inflatable cavity filling member is a balloon.16. The catheter assembly of claim 14, wherein the inflation fluid isradioabsorptive.
 17. The catheter assembly of claim 7, wherein theelongate shaft has a vacuum lumen and at least one port in the elongateshaft proximal or distal to the cavity filling member which is in fluidcommunication with the vacuum lumen to facilitate application of avacuum within the body cavity.
 18. The catheter assembly of claim 7,comprising a radioabsorptive portion surrounded by the cavity fillingmember.